Performance and isolation improvements for digitally controlled AC attenuation and protection circuits
AssigneeButler Engineering LLC
InventorJoel Butler
Life of this patent
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Abstract
A protection and attenuation circuit for sensitive AC loads is described. The circuit provides AC power protection and attenuation utilizing high-efficiency switch-mode techniques to attenuate an AC power signal by incorporating a bidirectional, transistorized switch driven from a pulse width modulation signal, PWM. The circuit monitors characteristics of the AC power signal driving a known load and characteristics of the load or other elements and determines the duty cycle of the pulse width modulated signal, PWM, based upon the duration and amplitude of the over-voltage, over-current, over-limit or other event.
Claims20
A method of protecting AC loads, the method comprising:
- monitoring one or more characteristics of an AC signal on an electrical line in communication with the AC load, wherein the monitoring is performed by a controller;
- and
- attenuating the AC signal using the pulse width modulated signal from the controller by generating a pulse width modulated signal based on the one or more characteristics of the AC signal to control a switching stage connected to the electrical line carrying the AC signal and controlled by the controller;
- wherein the controller is isolated from at least the switching stage and a signal conditioning stage by one or more electrical isolation stages, the signal conditioning stage providing a signal indicative of the one or more characteristics of the AC signal, and wherein the controller is electrically isolated from the AC signal such that the controller electrically floats relative to the AC signal.
A method for protecting multiple AC loads, the circuit comprising:
- monitoring one or more characteristics of a plurality of AC signals using a controller and a plurality of signal conditioning stages connected to the controller and each signal conditioning state providing a signal indicative of the one or more characteristics of the associated AC signal, wherein each AC signal is on an electrical line in communication with an associated AC load;
- and
- generating a pulse width modulated signal for each of the AC signals based on the one or more characteristics of the plurality of AC signals using a plurality of switching stages, each of the plurality of switching stages connected to the electrical line carrying the associated AC signal and controlled by the controller, wherein each of the switching stages attenuates the associated AC signal using the pulse width modulated signal from the controller;
- isolating the controller from at least the plurality of switching stages and the plurality of signal conditioning stages using one or more electrical isolation stages, wherein the controller is electrically isolated from the plurality of AC signals such that the controller electrically floats relative to the plurality of AC signals.
Dependencies are inferred from the claim text.